Growth and characterization of InAs/GaSb type-II superlattice for long-wavelength infrared detectors

摘要

We report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi- insulating GaAs substrate for long wavelength IR detectors. Photoconductive detectors fabricated from the superlattices showed 80 percent cut-off at 11.6 $mu@m and peak responsivity of 6.5 V/W with Johnson noise limited detectivity of 2.36 $MUL 10$+9$/ cmHz$+1/2$//W at 10.7 $mu@m at 78 K. The responsivity decreases at higher temperatures with a T$-$MIN@2$/ behavior rather than exponential decay, and at room temperature the responsivity is about 660 mV/W at 11 $mu@m. Lower Auger recombination rate in this system provides comparable detectivity to the best HgCdTe detectors at 300K. Higher uniformity over large areas, simpler growth and the possibility of having read-out circuits in the same GaAs chip are the advantages of this system over HgCdTe detectors for near room temperature operation.